This is very different from the global market share, where Android has 45% more.
https://www.techrepublic.com/article/ios-vs-android-market-s...
That's why Apple has higher profits than all other mobile operators combined!
This case is about US antitrust law, so what happens outside US borders isn't really that important, except as far as it affects the companies' revenues and profits. Supposedly, the actions of any antitrust action are to protect consumers/the general public, but what that really means is consumers in the US. Consumers outside the US are irrelevant. And the simple fact is that, by your own numbers, consumers in the US are mostly using iOS, not Android.
Regardless, 42% (in the US) is still a huge market share. Huge doesn't have to mean majority or even plurality.
For example, there's currently an ongoing anti trust case against "Al’s Asphalt Paving Company"
https://www.justice.gov/atr/case/us-v-als-asphalt-paving-com...
With the extra clarification that just the size of the company or its market share aren't in and of themselves enough to constitute a crime. It's how the company acts once it has that power that constitutes the crime.
You could be a huge company, or dominate a market and still not run afoul of anti-competitive laws because you didn't abuse the position [0]. The abuse of position particularly (or only, depending on jurisdiction probably) if it brings harm to consumers is what lands a company in hot water.
[0] https://thehustle.co/originals/the-worlds-cutest-monopoly
I'm not sure in what world 42% isn't huge when it comes to market share. iOS having a majority isn't really relevant to this point.
And regardless, GP didn't say "in the US"; globally, they are far ahead of iOS. Sure, this anti-trust action is a US matter, but a break-up would absolutely affect Google globally.
Not in the US they don't; it's a minority share, split across many different manufacturers who all have their own flavor of Android, their own (crappy) app stores and pre-loaded crapware apps, etc. Apple has a clear majority of the US smartphone market (and it's a vertical monopoly, with Apple controlling the phone hardware and the app store and not allowing any alternatives), but no one's looking at breaking them up.
>I think these two being open source is a major reason why they have been so successfully adopted.
iOS isn't open-source, and it has a commanding majority of the US smartphone market.